hello,

I recently had a 56 checked for purchase by a mechanic, he tested for a blown head gasket with a block test kit. I watched as he did it and with-in 45 sec. the blue liquid turned a muddy blue yellow, almost a light green. The mechanic said this was signs of a blown head gasket.

The owner took the truck to his mechanic, ran the same test, color stayed blue (no hydrocarbons). He also looked for bubbles in the radiator water and there was non. So now there is a positive and a negative reading. The owner then took it to a third party mechanic and had him run the same tests, again got a negative reading.

I have seen the receipts for the tests and am not sure what to think at this point.

Is there anyway that this would give different results? the truck not being warmed up enough? Any suggestions would really help...

thank you

 

I think the only way to confirm this is with “a cylinder leak down test” which is actually just putting compressed air into each cylinder by a special hose / fitting , if it’s a head gasket you will know.

 

I am not familiar with that test but I can say that there are many ways in which a head gasket can fail, not all of which involve hydrocarbons in the water. A gasket can blow between cylinders, between a cylinder and a water passage, between a cylinder and an oil passage, etc... As Old F1 said, a cylinder leak-down test will say alot about the condition of each individual cylinder, including the head gasket, valve seating, and piston ring wear.

 

hi guys, thanks for the reply,

there was a compression test done. The readings were (1)115 (2)125 (3)125 (4)125 (5)120 (6)125. Do you think this would confirm an issue with the head gasket or could it be something else going on?

 

There is nothing in those readings that would either confirm or refute a head gasket problem to me. If the readings in 2 adjacent cylinders were low then one could surmise that there was a breach between the cylinders, but just having one reading a bit low isn't enough in and of itself to say that a head gasket is the problem. That cylinder may have a bit more wear on the rings, a leak around a valve, or various other reasons why it's 10 lbs low. I don't know what your reasoning is with regard to this truck but if it were me I would calculate the cost of a valve job into the purchase price, buy the truck, and then pull the head and do the necessary repair work. I would find more peace of mind in knowing the state of the engine AFTER I worked on it than to take the risk on an unknown.

 

Thank you CharlieLed,

I think that is the best idea, then I will know exactly whats going on. Ill let you know how it goes.

thanks again